1. Field of the Invention
The disclosed subject matter relates to an amplifier design, of a type using magnetic energy. The disclosed subject matter also relates to low frequency power amplifiers.
2. Background of the Invention
In design of low frequency power amplifiers, it is desired to provide low frequency power amplification in a manner that minimizes amplifier size and weight. Current low frequency power amplifiers are relatively large and heavy. This is because present amplifiers contain magnetic components which must provide operational function at the output signal frequency. Examples of magnetic devices used in the magnetics are transformers and inductors.
The size of a magnetic device (transformer or inductor) varies to a first approximation linearly and inversely with frequency, which means that a magnetic device operating at a higher frequency may be manufactured to be much smaller than one having comparable performance characteristics, but operating at a lower frequency. Thus for a low frequency power amplifier, the size and weight of the magnetics will be many times greater than if the amplifier could be built with all magnetics operating at a switching frequency which was orders of magnitude higher than the desired output signal frequency.
U.S. Pat. No. 5,815,384, to Hammond, et al. describes a transformer circuit in which an AC switching stage preferably generates pulses at a frequency which may be up to several orders of magnitude higher than a line frequency, typically 60 or 400 Hz and having a duty cycle which may be up to about 98-99% of the pulse period. The circuit includes a transformer which requires less core volume and mass than conventional transformers, and includes a rectifier for transforming a first time varying input signal, such as a sinusoid or saw tooth signal, into a full-wave rectified voltage signal.